JPA: How can an @Embeddable object get a reference to its owner?

Question

I have a User class that has @Embedded a class Profile. How can I give the instances of Profile a reference to their owner the User class?

@Entity
class User imp         


        

Answer 1

Assuming JPA rather than strictly Hibernate, you might do this by applying @Embedded to a getter/setter pair rather than to the private member itself.

@Entity
class User implements Serializable {
   @Id @GeneratedValue(strategy = GenerationType.IDENTITY)
   private Integer id;

   @Access(AccessType.PROPERTY)
   @Embedded
   private Profile profile;

   public Profile getProfile() {
      return profile;
   }

   public void setProfile(Profile profile) {
      this.profile = profile;
      this.profile.setUser(this);
   }

   // ...
}

However, I would question whether an embedded entity is what you want at all in this case, as opposed to a @OneToOne relationship or simply "flattening" the Profile class into User. The main rationale for @Embeddable is code reuse, which seems unlikely in this scenario.

Answer 2

Refer to the official documentation ,section 2.4.3.4. , http://docs.jboss.org/hibernate/stable/annotations/reference/en/html_single/ , you can use @org.hibernate.annotations.Parent to give the Profile object a back-pointer to its owning User object and implement the getter of the user object .

@Embeddable
class Profile implements Serializable {

   @org.hibernate.annotations.Parent
   User user; // how to make this work?

   setURL(String url) {
      if (user.active() ) { // for this kind of usage
         // do something
      }
   }

   User getUser(){
       return this.user;
   }

   // .. other properties ..
}